The administration is deporting fewer criminal aliens than it did last year, according to new statistics released Tuesday that undercut President Obama’s justification for his new amnesty, which he said was intended to free agents to focus on the most dangerous of criminals by focusing on “felons not families.”

Instead, both arrests and deportations of criminal aliens are down about 30 percent through the first six months of fiscal year 2015, signaling that agents, who have been told to stop focusing on rank-and-file illegal immigrants, have not been able to refocus on criminal illegal immigrants instead.

The data, released by House Judiciary Committee Chairman Robert W. Goodlatte at the beginning of a hearing with U.S. Immigration and Customs Enforcement Director Sarah Saldana, also showed that the 30,558 criminal aliens ICE knowingly released back into the community in 2014 had amassed nearly 80,000 convictions, including 250 homicides, 186 kidnappings and 373 sexual assaults.

“The nonsensical actions of this administration demonstrate its lack of desire to enforce the law even against unlawful aliens convicted of serious crimes,” Mr. Goodlatte said.

Ms. Saldana said she’s required under the laws passed by Congress to grant due process to everyone, and said both court decisions and federal law require her to make judgments about whom to hold.

“Even the Congress contemplated some people would be released,” Ms. Saldana said.

But she said she’s also taken steps to require senior managers to review the releases in the future, which she said should being consistency and a more thorough review to the process.

“I myself have a concern — are we making the proper decisions?” she said.

According to the statistics, the aliens released by ICE had amassed 13,636 convictions for driving under the influence, 1,589 weapons offenses, 994 aggravated assaults, 56 arsons and 31 smuggling offenses.

The Obama administration has claimed that many of those releases are required by court order stemming from a years-old Supreme Court ruling, Zadvydas v. Davis, that says immigrants can’t be held indefinitely and if their home countries won’t take them back, they must eventually be released.

But the new numbers suggest those released are a small fraction. Of the nearly more than 30,000 criminal aliens released, only 2,457 were cut loose because of considerations stemming from the Zadvydas ruling, the House committee said. And for the serious crimes, only about half the homicide convictions and a third of the kidnapping convictions were Zadvydas-related releases.

Ms. Saldana said federal law instructs her agents to take account of how old the crimes are when deciding whether to continue detaining someone.

ICE also says that even when people are released from detention, they are still being monitored and are supposed to check in, and to return for their court hearings.

Even as she took fire from Republicans for lax enforcement, Ms. Saldana faced criticism from Democrats who said her agents are still doing too much to go after rank-and-file illegal immigrants.